feat: Cursor, Codex CLI, Cline, OpenCode, and Windsurf packages

[nathanschram]

Phase 5: Remaining Platform Packages (v1.10.0)

Context

After Gemini CLI and Copilot, five more platforms need distribution packages. Each has different capabilities and packaging requirements.

Platform Capabilities Summary

Platform	Skills	Hooks	Agents	Rules	Package Format
Cursor	yes	4+ events	yes (v2.4)	.cursor/rules/	Plugin marketplace
Codex CLI	yes	2 (exp)	yes	no	.agents/skills/
Cline	merged	3 events	read-only	.clinerules/	.clinerules/hooks/
OpenCode	yes	partial	yes	partial	opencode.json
Windsurf	yes	enterprise	limited	.windsurf/rules/	.windsurf/skills/

Deliverables

1. platforms/cursor/ — Plugin with skills, agents, hooks, .cursor/rules/
2. platforms/codex/ — .agents/skills/ format for Codex CLI
3. platforms/cline/ — .clinerules/ with hooks (3 events, macOS/Linux only)
4. platforms/opencode/ — opencode.json + .opencode/agents/
5. platforms/windsurf/ — .windsurf/skills/ + .windsurf/rules/

Verification

• Each package follows the tool's expected directory structure
• Skills activate on relevant prompts where supported
• Hooks fire on supported events

Part of the Cross-Platform ContextDocs Strategy. Depends on #18.